Abstract Detail

Ecological Section

Antlfinger, Ann [1], Garabrandt, Marjorie [2].

Analysis of 25 years of demography on a Nebraska population of Panax quinquefolius L. (Araliaceae).

In 1987, we discovered an undisturbed population of Panax quinquefolius in Omaha, NE, which is on the western edge of its range. We have monitored the status of this population (called Neale Woods) by estimating the annual growth rate, stage structure, and seedling recruitment. Individuals are scattered over a large slope in groups of 1-45 each. A total of 338 plants have been permanently numbered since 1987. Each May, a census was made, plant height measured, prongs and leaflets counted, and the presence of an inflorescence noted. Fruit production was determined in July or August. The size of the Neale Woods population has varied from 49 marked plants in 2012 to 140 in 2001, with an average of 113. Most years, the majority of plants had three or four prongs, suggesting the population had persisted for a long time. A few of the 3-prong (10%) but none of the 4-prong plants marked in 1987 are alive. Increased browsing was detected beginning in 1997. Browsing led to absence in the following year, regression to a smaller stage class, or remaining in the same stage class. The population shifted to a younger structure in 2001. In 2012, 4-prong plants were observed again. The mean annual growth rate for the Neale Woods population was 0.99 (se = 0.03) over 21 transitions (range = 0.7-1.2). Thus, the population is stable. A depletion curve, based on the multi-aged original sample of plants, suggested a half-life of 11 years for the Neale Woods population. The number of new seedlings recruited ranged from 0-22, representing less than 5% of the total population. Seedling survival decreased steadily with age. On average, only one-third of the cohort survived 10 years. Our results show that the Neale Woods population will maintain itself if left undisturbed. Therefore, harvesting is not advised.

Broader Impacts:

1 - University of Nebraska at Omaha, Biology Department, 6001 Dodge St., Omaha, NE, 68182, USA
2 - Iowa Western Community College, Biology Department

Keywords:
Demography
Ginseng
population structure
Medicinal plant.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Grand Salon A - D/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:45 PM
Number: PEC031
Abstract ID:913
Candidate for Awards:None